Biomedical subjects
A L Huddleston
Publications and source records attributed to A L Huddleston.
Compton scatter densitometry in cancellous bone.
A single-source low-energy Compton densitometer has been used to investigate the effects of multiple scattering on density determinations. The relative electron density and mass density were determined in samples of known density, and in samples of human cancellous bone tissue. The influence of sample diameter on the measured relative electron density of known samples was investigated. The measured value was strongly dependent on the diameter and the density range of the sample. The bias inherent in the density determination which is attributable to multiple scattering and attenuation in human femoral bone was evaluated, and a correction for these effects is suggested for clinical measurements.
The early detection of osteoporosis by Compton gamma ray spectroscopy.
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The effectiveness of glass lenses in reducing exposure to the eyes.
A study was done to determine the degree of radiation protection afforded by various types of prescription lenses, including commercially available lead glasses. A wide variation in measured attenuation was found. Two commonly available types of prescription lenses were found to provide greater than 92% attenuation of the x-ray beam generated at 108 kVp.
The modulus of elasticity of human cortical bone: an in vivo measurement and its clinical implications.
The modulus of elasticity was derived by combining the velocity of ultrasound measurements and photon absorption (Norland-Cameron method) in human cortical bone (proximal radius) in vivo. The results compare favorably with published values of the elasticity modulus obtained in vitro. Values obtained for a heterogeneous group of patients with bone and joint complaints differed from those of normal volunteers.
Geometrical considerations for Compton scatter densitometry.
The determination of the physical density by Compton scatter densitometry is dependent upon the geometry used for the measurement. The diameter of the sample, the density range, and the scattering volume size and shape influence the relative electron density values obtained by such a system. This work presents the results of an experimental analysis of these parameters in which the importance of each is evaluated for samples of known density. A bias in the computed Compton density, due to multiple scattering and attenuation, is defined; and an expression relating the density bias to these geometrical parameters is presented. The importance of applying corrections to the computed physical density for samples of large diameter and/or high density (cortical bone tissue and large diameter cancellous bone tissue) is discussed.